Cassiopeia was the Queen of Ethiopia. She is commonly depicted as a lady on a throne, upside down for part of the year. From our latitude (northern Utah), the constellation is circumpolar, meaning that it never sets. It is close enough to the north celestial pole that, if we could hide the Sun, we would see Cassiopeia simply circling the north star over a 24-hour period.

10 pm, MDT, from Salt Lake City, image credit: Starry Night Pro software

It may be difficult to see a lady on a throne in the stars, so I see Cassiopeia as a lazy ‘w’ shape, currently in the northeastern sky at 10 pm, MDT. Using the image below, we can find the ‘w’ shape on its side, about 1/3 of the way up the sky from the northeastern horizon. The distance between the  two end points of the ‘w’ is about 15 degrees. The distance from the bottom of the ‘w’ to Andromeda is also about 15 degrees.

Use the 'w' of Cassiopeia to find M31, the Andromeda Galaxy

M31 is difficult to see from a city or suburb–the darker the sky, the better. Nevertheless, it can be seen without the aid of binoculars or a telescope. This galaxy contains around one trillion stars and is about 5 times the size of our Milky Way galaxy. It is over 2.5 million light years away.

Most of the stars you can see individually in the night sky are all pretty close to us–within a couple thousand light years. The Milky Way, that streak of cloudy light we see across the sky, is a few thousand to a few tens of thousands of light years away. Our entire Milky Way galaxy, containing around 200 billion stars, is probably 100,000 light years across. The Andromeda Galaxy, the nearest major galaxy to us, is over 2.5 million light years away, and there is a lot of nothing between us and it.

Space is a great big empty…

Does this sound like you? Join Clark Planetarium for a Job Fair on Tuesday, Sept. 14, 2010 where we will be interviewing for part-time floor staff positions.

Our part-time staff are the front line of our organization, working to enhance the Clark Planetarium experience by engaging with customers on a multitude of levels. During any given shift, floor staff may be assigned to one or more of the following tasks: Selling tickets and assisting customers, expertly operating the information booth, working in the amazingly cool Planet Fun Clark Planetarium Store, cashiering, stocking and taking inventory and serving customers at the concession counter.  Our floor staff also act as ushers for the ATK IMAX and Hansen Dome Theatres as well as introducing the show they are about to see. You may also be asked to guide customers on brief tours through our 10,000 square feet of exhibits.

Part-time positions are available for evening and weekend shifts. Starting wage is $7.50 per hour (with a possible increase after successfully completing a probationary period).

Job Fair Schedule:

1 p.m. – Complete Application

1:30 p.m. – Presentation in Hansen Dome Theatre

2 p.m. – Brief individual interviews

We look forward to seeing you there!

You have a good opportunity this week to observe Venus and see the dynamic geometry of the solar system in action.

While you are looking at Venus, appearing like a diminutive first-quarter moon in your telescope’s eyepiece, consider this:

Exactly four hundred years ago Galileo used his own primitive telescope to observe Venus, and through it he saw that as the nights went by Venus exhibited phases similar to those shown by our moon.

Galileo reasoned that the only way that Venus could present these phases to us on Earth is if Venus and Earth were both planets orbiting the Sun.  Prevailing thought at the time held that Earth was “fixed” in the heavens and that everything in the universe revolved around Earth.

Galileo's sketches of the phases of Venus

Galileo’s observations of Venus provided hard evidence in support of Copernicus’ revolutionary assertion that we live in a heliocentric (Sun-centered) rather than geocentric (Earth-centered), universe.

Telling people in the early 1600’s that the Sun, not Earth, was the center of everything was a dangerous thing to do.  For centuries the conventional wisdom was that Earth (and by extension, mankind) was the center of the universe and everything in the heavens revolved around us.  It was the ultimate ego-trip.

Galileo was saying to the world, “Copernicus was right. Earth is a planet, like Venus, and it orbits the Sun. Night and day are the result of our planet rotating.”  That was very upsetting to the dominant belief of the day.  Galileo was charged with heresy, a crime punishable by death. He avoided execution at the hands of the Inquisition only by recanting his belief in a heliocentric universe, and he was sentenced to house arrest for the rest of his life.

For your own observations of Venus as it goes through its phases, you will need a modest telescope with at least 30x magnification.

Venus!

Look to the west soon after sunset  this week – Venus is the super bright object just above the western horizon.

Don’t dawdle, though.  Venus is moving rapidly from night to night, and will be no longer visible after sunset by about September 6^th.

Venus will then be passing between Earth and the Sun for the next couple of months but will re-emerge as the “Morning Star” against the pre-dawn eastern horizon this November through February.

Happy viewing!

Next Tuesday, Aug. 31, 2010,  at 9:05 a.m. (MDT), ATK and NASA will host a horizontal ground test firing of the Ares DM-2 (Ares Development Motor – 2) five-segment solid rocket motor…and you’re invited!

In fact, if you are a twitter user and would like to take advantage of an exclusive, up close view of the test, you can register with @ATKRocketNews (deadline to register is Aug. 26) on twitter and view the testing from the VIP launch site. You can also follow the #DM2 hash tag on the day of the event for the latest updates from the launch site.

2009 DM-1 test, Corinne, UT

The DM-2 is a five-segment rocket motor that is an upgraded version of the Shuttle’s 4-segment booster. This DM-2 test is being held in the morning as a “cold motor” test in which the motor will be cooled to 40 degrees F to measure the solid rocket motor performance at low temperatures.

If you would like to view next week’s test from the public viewing area rather than participating in the tweetup, travel approximately 20 miles west of Corinne, Utah, to the observation area located along State Road 83 North.

Lastly, we encourage you to post comments about the test here on our blog, or visit our facebook profile to upload any fan photos you would like to share.

Disclaimer: ATK  is a financial supporter of Clark Planetarium. They sponsor the ATK IMAX Theatre through annual cash and in-kind donations.

The Dark Side of the Moon gala will be held at Clark Planetarium on Thursday, Sept. 23, 2010 from 6:30 – 10:30 p.m. Tickets for the event are $100 ($125 if purchased after Sept. 17). Click here for tickets and additional information.

Earth passes through this particle stream every year about August 12. This year the peak of the Perseid meteor shower is August 12 at 6 p.m. MDT, only a few hours before nightfall. An observer away from city lights might see about 60 meteors per hour. Early morning observers can also see the planet Jupiter in the south-eastern sky. A thin crescent moon sets before 10 p.m., so moonlight will not interfere with observing the shower this year.

Where is the best place to look? Look up. While the meteors will appear to originate from the constellation Perseus in the northeast, they can be seen all over the sky. The best time to observe the shower is from about 1:00 to 5:00 a.m. (on the morning of the 13th) when Utah is facing into the meteor stream. If you cannot observe during those hours, do not despair, some meteors will still be visible as soon as the sky is dark.

The most important aspect of observing a meteor shower is to be away from city lights. No equipment is needed to observe, so leave the telescope at home. Meteor showers are best seen with the eyes alone, taking in as much of the sky as possible. However, a reclining lawn chair and mosquito repellant may help make the observing session more comfortable.

Hosted at Clark Planetarium by board members and staff, this fundraising event features delicious food from some of Salt Lake’s best restaurants, live and silent auctions and we will close out the evening with a presentation of Pink Floyd’s Dark Side of the Moon cosmic light show.

Proceeds from the event benefit Clark Planetarium’s community outreach initiatives focusing on space science education. Since 2003, the planetarium has worked with community and state educators to provide unique and valuable astronomy education programs for students, teachers and the general public.

Design provided by RIESTER

“Community support for our programs is vital to our ability to create and support science education programming to Utah school children. Our facility, staff, exhibits and advanced technology allow us to place students and their teachers in the model, making difficult concepts easier to understand. ” said Seth Jarvis, director of the planetarium.

Each year more than 75,000 school children are served through Clark Planetarium visits and the AstroVan outreach program. The Dark Side of the Moon fundraising gala will give attendees the opportunity to experience the educational exhibits and programs in a fun, party-like atmosphere while helping to fund the planetarium’s educational mission.

The Dark Side of the Moon gala will be held at Clark Planetarium on Thursday, Sept. 23, 2010 from 6:30 – 10:30 p.m. Tickets for the event are $100 ($125 if purchased after Sept. 17) and can be purchased online.

1970’s party apparel is encouraged and all guests will receive a string of pearls compliments of Overstock.com.

The last misconception, The Earth’s axis changes the direction of its orientation throughout the year, is easily dismissed with the help of Sir Isaac Newton.   Isaac Newton’s first law of motion states that an object in motion will keep doing whatever it’s doing until disturbed by some force.  Because the forces acting on Earth are VERY small, the axis continually points toward Polaris throughout the entire year.

We have learned that the seasons are caused by the fact that Earth is tilted on its axis as it orbits the sun.    In the summer, this makes the sun quite high in our sky, which keeps the sun’s energy concentrated, warming the ground.  In the winter, the tilt remains the same but since Earth has gone half way around in its orbit, the sun is now low in our sky, which means that the light is more spread out, providing less energy to each square foot of ground. The result is that we cool off as winter approaches.

Experiment:

Try holding a flashlight pointed straight down to make a spot of light on the floor. Observe the brightness of the spot and also note the shape of the spot. If you put a piece of paper on the floor, you can trace the size and shape of the spot on the paper.

Now change the angle of the light. Move the flashlight so that its beam hits the ground at an angle.  Keep the light pointed at the same spot on the floor and at about the same distance. You should see some change in the light. This change can be marked on the same piece of paper as a comparison.

What changes did you see? Was there any change in the apparent brightness of the light? Was there any change in the shape of the spot of light?

Observe how the intensity and brightness change according to the angle of the flashlight.

Clark Planetarium and The Utah Museum of Fine Arts have partnered to bring you the complete Maya experience.  Come to Clark Planetarium to see Tales of the Maya Skies which tells of Mayan astronomy, culture and achievement.  Tales of the Maya Skies, produced by Chabot Space and Science Center, uses full dome digital technology to transports us back into the world of the Maya. 

Follow your visit with a TRAX ride over to UMFA to Las Artes de México where you will examine three millennia of tradition and change across the broad spectrum of Mexican art and culture.  The Las Artes de México gallery provides an in-depth look about the religion, art, architecture and general culture of the Mesoamerican civilizations.

Enjoy this experience at a discounted rate!  Visit Clark Planetarium’s Facebook page to receive a BOGO coupon to both locations.

Tales of the Maya Skies plays in the Hansen Dome Theatre at 1:30 p.m. and 5:30 p.m. daily.  View the trailer and buy tickets on our website.

Regardless of the predicted peak hour, the best time to watch for meteors is during the pre-dawn hours (after midnight), your local time, when your position on the Earth is moving into the meteoroid stream. Meteors (commonly called ’shooting stars’ or ‘falling stars’) are actually little more than grains of sand, dust and small pebbles that burn up high in the atmosphere as they fall down to Earth at very fast speeds. The Perseids are traveling at around 60 kilometers per second (130,000 miles per hour!).

Meteor showers are the result of a passing comet. Comets are mountain-sized objects made of frozen gasses, water, and dirt. As the comet approaches and rounds the Sun, it sublimates (turns from a solid directly into a gas, like dry ice), creating a cloudy sphere, called the coma, around the nucleus. The solar wind pushes on the coma forming the long comet’s tail, which always points away from the Sun. It is the gritty particle material of the comet that we see as meteors when the Earth passes through this debris field left behind long after the comet has passed. The comet may not come back for many years, but we will enjoy the meteor shower at about the same time every year. The Perseids are the result of comet Swift-Tuttle, which last passed the Sun in 1993 and won’t be back for another 118 years.

The name ‘Perseids’ comes from the comet Perseus. As you watch Perseid meteors, all over the sky, you can trace backward the familiar streak of light seen. No matter which direction the meteor is headed, the streak of light can be traced backward toward the constellation Perseus. Doing this for several meteors will show that there is a point of convergence for all these backward-traced paths. This point, called the ‘radiant,’ which will be in Perseus.

No need for a telescope or binoculars. Just get comfortable, get out of the city if you can, and enjoy the Perseid meteors this week.